ZETRON 30 Worldpatch User manual

ZETRON
Model 30 Worldpatch with Selcall
Instruction Manual
Part No. 025-9431B
Please check for change information at the begining of this manual.
Copyright © 1991 - 2000 by Zetron, Inc.
All Rights Reserved

Table of Contents
CHANGE INFORMATION
WARRANTY
1. INTRODUCTION
INTRODUCTION .............................................................. 1-1
FEATURES....................................................................... 1-1
2. SPECIFICATIONS
GENERAL SPECIFICATIONS ......................................... 2-1
TELEPHONE INTERFACE SPECIFICATIONS ............... 2-1
RADIO INTERFACE SPECIFICATIONS.......................... 2-1
ADDITIONAL SPECIFICATIONS..................................... 2-2
PAGING FORMATS ......................................................... 2-2
3. OPERATION
OVERVIEW ...................................................................... 3-1
BASIC CALL TYPES ........................................................ 3-1
Phone-to-Mobile Calls ................................................. 3-1
Mobile-to-Phone Calls ................................................. 3-2
Mobile-to-Mobile Calls................................................. 3-2
Once a Call is in Progress........................................... 3-2
Remote Programming Access .................................... 3-3
MODEL 30 FEATURES.................................................... 3-3
DTMF or Pulse Dial Regeneration .............................. 3-3
Toll Restriction............................................................. 3-4
Call Limit Timer ........................................................... 3-4
Mobile Activity Time .................................................... 3-4
Courtesy Tone............................................................. 3-4
Repeat Enable............................................................. 3-4
Interconnect “Security” ................................................ 3-4
Direct to Air.................................................................. 3-5
Autodial........................................................................ 3-5
Hook-Flash .................................................................. 3-5
Non-DTMF Access to Phone Line............................... 3-5
Auxiliary Output Control .............................................. 3-5
Call Alert ...................................................................... 3-6
Dual Function Connect Button .................................... 3-6
SIMPLEX OPERATION.................................................... 3-6
Simplex Modes............................................................ 3-6
Simplex Timers............................................................ 3-7

Table of Contents
(Continued)
OPTIONS.......................................................................... 3-8
4. PROGRAMMING
PROGRAM MODE ACCESS ........................................... 4-1
ENTERING A PROGRAM COMMAND............................ 4-1
PROGRAMMING COMMANDS ....................................... 4-2
Access and Disconnect Codes ................................... 4-2
Mobile-to-Phone Pulse or DTMF Dialing..................... 4-3
Number of Rings-to-Answer........................................ 4-3
Single Digit Access Code Validation ........................... 4-3
Dial Regeneration Timeout Timer ............................... 4-3
Hook Flash .................................................................. 4-4
Call Waiting Alert......................................................... 4-4
Limit Phone Access to Autodials................................. 4-4
Toll Restrict Digits ....................................................... 4-4
Ringout Mode .............................................................. 4-4
Optional Security Code for Direct to Air ...................... 4-5
Repeat Audio Control .................................................. 4-5
Call Answer Mode ....................................................... 4-5
Morse Code Station ID ................................................ 4-5
Interconnect Courtesy Tones ...................................... 4-6
Half-Privacy Mode ....................................................... 4-6
Call Limit Timer ........................................................... 4-7
Mobile Activity Timer ................................................... 4-7
Set Operating Mode .................................................... 4-7
Sample VOX Before Issuing Dial Tone ....................... 4-8
Select Paging Format.................................................. 4-8
Two-Tone Paging Parameters .................................... 4-8
DTMF Paging Parameters........................................... 4-9
Mobile-to-Mobile Paging.............................................. 4-9
Autodial Numbers........................................................ 4-9
Dial Tone Disconnect .................................................. 4-10
Non-DTMF Mobile Access .......................................... 4-10
Dual Function Connect Button .................................... 4-10
Multiple Second Dial Tone .......................................... 4-10
Repeat Courtesy Tone ................................................ 4-11
Simplex Sample Rate.................................................. 4-11
VOX Hold Time ........................................................... 4-11
Automatic Sample Window Setup............................... 4-11

Table of Contents
(Continued)
COR Hold Time ........................................................... 4-12
Busy Tone Detector..................................................... 4-12
PL Strip Output............................................................ 4-12
Auxiliary Output Control .............................................. 4-12
Program Access Code ................................................ 4-13
Reset All Parameters to Factory Default..................... 4-13
Installation Tests ......................................................... 4-13
Exit Program Mode...................................................... 4-13
TWO-TONE TABLES ....................................................... 4-14
Two-Tone Timing ........................................................ 4-14
Two-Tone Tone Groups .............................................. 4-14
Two-Tone Code Plans................................................. 4-16
5. INSTALLATION
INSTALLATION WARNING.............................................. 5-1
GENERAL......................................................................... 5-1
EQUIPMENT REQUIRED FOR INSTALLATION............. 5-1
INSTALLATION PROCEDURE........................................ 5-1
TEST AND ADJUSTMENTS / INITIAL TURN-ON ........... 5-2
OPTIONAL DIGITAL VOICE DELAY ............................... 5-5
INSTALLING THE SELCALL OPTION............................. 5-6
6. REPAIR
IN CASE OF DIFFICULTY ............................................... 6-1
TROUBLESHOOTING ..................................................... 6-1
COR and Squelch Problems ....................................... 6-1
Unreliable Dialing or Misdialed Numbers.................... 6-1
Unable to Access Dial Tone or Answer a Call ............ 6-2
Intermittently Disconnecting During a Call .................. 6-2
MODEL 30 CONTROL BOARD (702-9321K) .................. 6-3
Parts List...................................................................... 6-3
Schematic.................................................................... 6-5
Silkscreen.................................................................... 6-8
7. PROGRAMMING LOG AND QUICK REFERENCE
PROGRAMMING.............................................................. 7-1
Programming Example................................................ 7-1
PROGRAMMING LOG AND QUICK REFERENCE ........ 7-2
AUTODIAL PROGRAMMING LOG.................................. 7-6

Table of Contents
(Continued)

WARRANTY
Zetron’s warranty is published in the current Zetron United States Price Book.
LIMITATION OF LIABILITY
Zetron makes no representation with respect to the contents of this document
and/or the contents, performance, and function of any accompanying software
and specifically disclaims any warranties, expressed or implied, as to
merchantability, fitness for purpose sold, description, or quality.
Further, Zetron reserves the right to revise this document or the accompanying
software and to make changes in it from time to time without obligation to notify
any person or organization of such revisions or changes.
This document and any accompanying software are provided “as is.” Zetron shall
not under any circumstances be responsible for any indirect, special, incidental,
or consequential damages or losses to the buyer or any third party arising out of
or connected with the buyer’s purchase and use of Zetron’s products or services.
COPYRIGHT
This publication is protected by copyright by Zetron, Inc. and all rights are
reserved worldwide. This publication may not, in whole or in part, be copied,
photocopied, reproduced, translated, or reduced to any electronic medium or
machine-readable form without prior written consent from Zetron, Inc.
The software in this product is protected by copyright by Zetron, Inc. and
remains the property of Zetron, Inc. Reproduction, duplication, or disclosure is
not permitted without prior written consent of Zetron, Inc.
TRADEMARKS
Zetron is a registered trademark of Zetron, Inc.
All other product names in this document are trademarks or registered
trademarks of their respective owners.

FEDERAL COMMUNICATIONS COMMISSION (FCC)
REGULATIONS
To comply with FCC regulations, the following requirements must be met:
1. The FCC registration number (EYBUSA-73432-OT-E), ringer equivalence
number (0.4 B), and interface jack (RJ11) must be reported to the telephone
company, if so requested.
2. This device must not be installed on coin-operated or multiparty telephone
lines.
3. The sum of ringer equivalence numbers for all devices connected to a single
telephone line should not exceed 5 for reliable operation.
4. Repair work on this device must be done by Zetron, Inc. or a Zetron-
authorized repair station.
This equipment has been tested and found to comply with the limits for a Class A
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in accordance with
the instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at
his or her own expense.
Changes or modifications not expressly approved by the manager of Zetron’s
compliance department can void the FCC authorization to operate this
equipment.

1-1
1. INTRODUCTION
INTRODUCTION
The Zetron Model 30 is a multi-mode, easy to use telephone interconnect.
Simplex VOX, simplex sampling, intelligent sampling, and half duplex modes
are supported. Digital voice delay is an available option to enhance simplex
operation.
Multi-digit DTMF access codes and toll restrict digits are selectable to eliminate
unauthorized use of the phone line. The Model 30 allows mobile DTMF or
regenerated pulse dialing. Repeat audio processing and transmitter control are
included to convert a duplex base station into a repeater, allowing dispatch
operation.
The Model 30 includes factory defaults for all programmable settings so that it
will function on any system straight out of the box, or may be customized easily
using a touch-tone telephone or DTMF equipped radio.
The Selcall option for the Model 30 allows the Worldpatch to offer both DTMF
and Two-Tone selective calling of mobile and portable radio users. This
capability can be used from the phone, or by radio users, to signal other radios in
the system. The mobile-to-mobile signaling is available in both half duplex and
simplex applications. This option can be installed at the factory, or in the field as
an upgrade kit. The programming in a Selcall unit is significantly different than
regular Model 30 programming, so the programming commands in Section 4
should be carefully reviewed even by technicians who have prior experience with
non-Selcall versions of the Model 30 Worldpatch.
FEATURES
•Simplex VOX, simplex sampling, simplex phone key control, intelligent
simplex, and half duplex modes
•Single phone line interface
•DTMF or regenerated dial pulse dialing
•Repeat audio and control for mobile to mobile calls
•Morse code station ID
•Programmable via DTMF telephone or DTMF radio
•Call progress and mobile ring-out tone generation
•Call limit and mobile activity timers
•First and second digit toll restriction

Section 1. Introduction
1-2
•Toll defeat access code
•1 - 9 digit DTMF connect code
•1 - 9 digit DTMF disconnect code
•Half-privacy mode for duplex installations
•Automatic setup mode aids installation for simplex sampling
•High-pass filter to remove mobile CTCSS
•Internal squelch circuit
•External input from CTCSS or DCS decoder to validate proper mobile
•Optional Digital Voice Delay for enhanced simplex operation
•Hook Flash capability
•Call Alert to let mobile users know that the phone is ringing during dispatch
operations
•Autodial numbers
•Non-DTMF Mobile-to-Phone Access
•Dual function Connect button
•Security password for Direct Air Access
•Repeat courtesy tone
•Auxiliary output control
•Up to 13 digit DTMF paging
•100 call and 1000 call two tone paging
•Single digit access code validation
•Automatic busy tone call disconnect
•Automatic dial tone call disconnect
•PL strip during paging

2-1
2. SPECIFICATIONS
GENERAL SPECIFICATIONS
Power 11-16V DC 150 mA
Temperature 0 to 65 degrees Celsius
Size 5.5″W x 6.25″D x 1.4″H
Weight 1.0 pound
TELEPHONE INTERFACE SPECIFICATIONS
Line Type End-to-End phone line
Connector RJ11 modular jack
Incoming Call Ring detection on tip-ring pair. Programmable number
of rings to answer.
Call Answer Off-hook, tip ring current draw
Call Disconnect Busy tone, Dial tone, Call Limit, Mobile Activity
timers
RADIO INTERFACE SPECIFICATIONS
PTT FET pull to ground
COR Noise detector
Tx Audio -40 to +6 dBm. Hi/Lo selector. 1 kΩoutput
Rx Audio -40 to +10 dBm. (25 mV to 6 Vp-p) Hi/Lo selector.
50 kΩinput.

Section 2. Specifications
2-2
ADDITIONAL SPECIFICATIONS
Indicators Phone, Carrier, Transmit, Power
Switch Connect / Disconnect
Station ID Morse Code, fixed 1200 Hz frequency and selectable
call sign
Prompt Tones Progress tones, error tones, and warning tones sent to
phone or mobile
Programming Programmable via DTMF phone, DTMF mobile
Data Retention EEPROM - data retention for more than 40 years
without power
Secondary
Protection
Telco high voltage clamps with protective fusing
elements
PAGING FORMATS
DTMF Format Pages consist of from 1 to 8 digits entered by the
caller, plus 0 to 5 additional digits that may be
strapped in the patch’s programming.
Strapped digits can be sent before or after the digits
entered by the caller.
Transmission speed is fixed at 8 digits per second.
Two-Tone Supports both a 100 call and a 1000 call
configuration.
In 100 call, the tone groups available are: Motorola 1,
2, 3, 4, 5, 6, A, B, Z, 10, 11 — GE A, B, C
Eight common two-tone timings are available (see
“Two-Tone Timing” in Section 4).

3-1
3. OPERATION
OVERVIEW
This section discusses the normal operations of the Model 30 Worldpatch. It is
divided up based on the types of operations performed. The operation of the
interconnect will depend on whether the SelCall or Mobile-to-Mobile calling are
enabled or disabled.
BASIC CALL TYPES
Phone-to-Mobile Calls
When the telephone line rings, the Model 30 will wait the number of
programmed RINGS TO ANSWER before reacting to the call. This allows for a
parallel phone to be manually answered before the Model 30 attempts to process
the call. What happens next depends on whether or not the SelCall feature is in
use.
If SelCall is disabled, the Model 30 will begin ringing out on the radio channel.
The Model 30 may be configured to ring either once and wait up to 1 minute for
an answer, or ring each time the phone rings for up to 1 minute. If a mobile has
not answered within this time, the call is terminated. Once a mobile answers, the
Model 30 will take the phone off hook and allow the call to progress. If the line
rings for 10 rings past the number of programmed RINGS TO ANSWER, the
phone will be answered and the user may enter the program access code to
remotely program the Model 30.
With paging enabled, incoming phone calls are answered after the appropriate
number of rings. Once answered, the caller will hear two beeps as a prompt to
enter the radio’s capcode. The page is then transmitted followed by ringing until
the mobile answers or the call times out at 1 minute.
When the Worldpatch is programmed for Direct-to-Air operation, the caller will
be placed directly onto the radio channel after the page is transmitted. Enabling
the Direct-to-Air security password, requires the caller enter a password before
being prompted to enter the called radio’s capcode.
Both DTMF and Two-Tone paging formats may be enabled in the Model 30.
This requires an added digit at the beginning of the capcode to specify the type of
page desired. A “1” tells the system that a DTMF page is to be placed and a “2”
specifies a two-tone page. For instance, if a DTMF paged radio had a capcode of
“456”, the caller would enter: “1456” when both paging formats were available.
Likewise, a two-tone capcode of “85” would be entered as: “285” in a dual
format Model 30 Selcall Worldpatch.

Section 3. Operation
3-2
Pressing the CONNECT button on the front panel while the Model 30 is on-hook
causes it to go off-hook and enter into the conversation mode.
Mobile-to-Phone Calls
To place a call, a mobile enters the DTMF ACCESS CODE (sign-on sequence)
and unkeys. The ACCESS CODE must be entered without unkeying between
digits or waiting more than 1 second between successive digits. The Model 30
will take the phone off-hook and send dial tone (phone audio) to the transmitter.
For simplex installations, the transmitter will be keyed for 2 seconds, then unkey
to receive mobile dialing digits. The Model 30 will regenerate the mobile DTMF
to the phone, or provide conversion from DTMF to pulse dialing until there is a
5-second gap in the entered digits. The MOBILE ACTIVITY and CALL LIMIT
timers are started as soon as the telephone is taken off-hook. During dialing, if
the mobile’s first digit matches a digit in the first digit-restricted string, the
Model 30 will terminate the call. The same applies for the second digit restrict
string and the second digit dialed.
If Mobile-to-Mobile calling is enabled in the Model 30, the radio user must enter
a steering digit along with the ACCESS CODE. Adding a “9” to the ACCESS
CODE sets up a Mobile-to-Phone call. The Model 30 will respond by prompting
for the phone number as usual.
Mobile-to-Mobile Calls
When Mobile-to-Mobile paging is enabled, radio users connecting to the Model
30 Selcall enter a steering digit after the Connect Code. This steering digit
specifies whether the user wants access to the phone line or to page another
mobile. Entering a “7” requests Mobile-to-Mobile paging. This is followed by a
page-type digit (if required) and the capcode. Mobile-to-Mobile paging is
available even in simplex systems.
Once a Call is in Progress
Once a call has been connected, the call may be terminated in one of seven ways:
1. Disconnect Code - A mobile may disconnect the call by sending the
disconnect code. The call is terminated immediately and 5 fast beeps are
sent to the mobile indicating the call is over. Once the disconnect code
sequence has been started, each additional digit must be sent within
1 second of the last, without dropping carrier between digits. If the user
unkeys between disconnect code digits, the sign-off attempt is ignored.
2. Busy Disconnect - If a busy tone is detected by the Model 30 during the first
20 seconds of a mobile originated call, the Model 30 will disconnect and
send 5 fast beeps to the transmitter. The busy disconnect feature may be
disabled by the installer, or enabled for the entire length of the call.

Section 3. Operation
3-3
3. Dial Tone Disconnect - If continuous dial tone is detected after the
conversation mode of a call has begun, the call will be terminated and 5 fast
beeps sent to the mobile. This feature may be disabled by the installer.
4. Mobile Activity - The mobile must transmit at least once during the mobile
activity interval. If not, the call will be terminated and the 5 fast beeps will
be sent to the mobile. During the conversation, a single beep will be sent to
the phone and the mobile every 3 seconds starting at 12 seconds before the
mobile activity timer expires. This beep serves as a warning to both the
telephone user and the mobile user.
5. Call Limit - Each call is limited in length. Once the call limit timer has
expired, the call is terminated and 5 fast beeps are sent to the mobile.
Double warning beeps are sent to the telephone and mobile every 3 seconds
starting 15 seconds before the call limit timer expires. If programmed to do
so, the Model 30 may allow the mobile to extend the call limit time by
pressing the “*” key.
6. Phone Party Disconnect - The phone party may disconnect the call by
entering a DTMF “#0”. The call will then disconnect in the same manner as
if the mobile had initiated the disconnect.
7. Connect Button - Pressing the connect button while the Model 30 is off-
hook terminates the call in progress and forces the Model 30 back into the
on-hook idle mode.
Remote Programming Access
The mobile user may enter the program access code to gain access to remote
programming.
MODEL 30 FEATURES
DTMF or Pulse Dial Regeneration
The Model 30 defaults to regenerating the DTMF digits received from the mobile
user to dial the telephone. This allows the unit to present a pre-set level and
quality of DTMF to the phone line regardless of conditions on the channel. This
function can also be programmed to translate the mobile’s DTMF into pulse
dialing, should that be required by the connected telephone service.
While dial regeneration is active, audio from the mobile unit connected to the
system is not passed to the telephone line.
Dialed number regeneration is a timed function. By default, the mobile user has 3
seconds to dial each digit of the phone number. This time may be programmed to
be from 0 to 60 seconds. Regeneration time must end before conversation can
take place. This can either be done by waiting until the regeneration timer lapses

Section 3. Operation
3-4
or by forcing it to end by sending a DTMF “*” as the last digit dialed. (The “*” is
not regenerated.)
Toll Restriction
The Model 30 will not allow a mobile to dial a telephone number whose first or
second digit is in either toll restrict table. These tables can both contain up to four
digits. Toll restriction may be turned off by programming both tables as blank.
A toll defeat code is provided to allow “privileged” users to avoid the toll
restriction when making calls. This code is used in place of the access code to
gain access to the phone line.
Call Limit Timer
The call timer determines the maximum time that a call may last before being
terminated. The call limit timer may be reset using a DTMF “*” if programmed
to do so. Double warning beeps are sent to the telco and mobile every 3 seconds,
starting 15 seconds before the call is terminated.
Mobile Activity Time
The mobile activity sets the amount of time that may elapse without the Model
30 detecting a mobile transmission. When this timer expires, the call is
terminated. This timer assures that if a mobile travels out of range (loses control
of the interconnect), the conversation will be terminated even though the mobile
cannot manually terminate the call. Single warning beeps are sent to the telco and
mobile every 3 seconds, starting 12 seconds before the call is terminated.
Courtesy Tone
A courtesy tone is a short 50 millisecond beep that prompts the phone party to
begin speaking. This is especially useful when phone callers are not aware that
they must wait for the mobile to unkey before speaking.
Repeat Enable
The Model 30 includes the capability to turn a duplex station into a carrier
controlled repeater. When enabled, the Model 30 will repeat audio any time it
receives carrier detection. After receive carrier drops, the transmitter is held up
for the programmable REPEATER TRANSMIT HOLD TIME.
Interconnect “Security”
Interconnect Security is intended to discourage casual eavesdropping. During a
phone call with the security disabled, the mobile audio is routed to the transmitter
(repeated). With security mode enabled, an annoying tone is sent to the
transmitter while the mobile speaks. This masks the mobile’s half of the
conversation to other listening mobiles or scanners.

Section 3. Operation
3-5
Direct to Air
The user may program the unit to place the received call Direct to Air. If this
function is enabled, it places the caller on the air without waiting to get a
response from the mobile user to complete the call. This type of operation is
particularly useful for in-house systems where the Model 30 is on an extension of
a PBX.
Autodial
The Model 30 allows up to 50 autodials to be stored for speed dialing. To access
the autodials, the user enters his/her connect code and, within 1 second, the
autodial number. For example, if the connect code is “*” and the mobile wishes
to autodial the phone number stored at location 5, the user enters “*5”, and the
number is dialed. Up to 16 digits may be programmed into each autodial slot.
Mobile users can be restricted to only accessing the phone by using the Autodial
numbers. If a mobile user initiates a call while this feature is enabled, that user
can only request a valid Autodial number. If the user tries to dial a regular phone
number or to access an Autodial slot that is empty (not programmed), the call is
be terminated and the Model 30 issues an error tone (warble) on the channel
before unkeying the transmitter.
Hook-Flash
The hook flash, when enabled, allows the mobile to flash the telephone line. For
example, if you are on a PBX system, the PBX may require a hook flash to
perform certain functions. To flash the line, the user sends a “*0” during a call.
Non-DTMF Access to Phone Line
When enabled, non-DTMF equipped mobiles can gain access to the phone line
by simply keying up four times in rapid succession. If four carrier signals are
received less than 1 second apart, the phone line will be taken off hook and
autodial #1 will be dialed. The phone side can disconnect the call by sending
“#0”.
Auxiliary Output Control
The Auxiliary Output allows an external device at the radio site to be controlled
with DTMF over the radio channel or from the phone. This is useful, for
example, to control an antenna switch for coverage of multiple areas. The
Auxiliary Output is controlled by entering different codes to turn on or off the
output. This can be accessed from either the radio or the phone. The factory
defaults for these codes are 567 to turn “on” the output and 890 to turn “off” the
output. These may be programmed by the user to be any code of up to nine digits
each. When the On code is decoded by the Model 30, the FET on the Auxiliary
Output will be switched on which pulls the open drain line to ground. The FET is
capable of sinking a maximum of 200 mA DC. The output stays in the assigned

Section 3. Operation
3-6
state until commanded to switch states. The output state is saved in the unit’s
non-volatile memory and is restored as set even if power is cycled.
Call Alert
When enabled, Call Alert allows the Model 30 to key up during an existing
Mobile-to-Mobile conversation and send two quick beeps over the air when a
telephone call comes in. The mobiles may then elect to stop their conversation so
one of them may answer the call.
Dual Function Connect Button
This is designed for installations where the Model 30 is used on an operator’s
desk to route calls between the office and the field. In normal operation when the
Connect button is pressed while the system is idle, the phone line is placed
directly on the air in conversation mode. Enabling this option instructs the Model
30 to ring out over the air to hail the mobile user when the button is pressed. If
the channel has activity, the phone line will be placed in conversation mode
when the button is pressed.
SIMPLEX OPERATION
Simplex Modes
There are six simplex modes.
Simplex VOX
This is the standard simplex mode that keys the transmitter using phone voice
(VOX) detection. When neither party is talking, the Model 30 watches for either
VOX or carrier detection. When the Model 30 detects VOX, it keys the
transmitter and allows the telephone audio to pass to the transmitter. When VOX
drops and the VOX HOLD timer expires, the transmitter is dropped and the
Model 30 returns to waiting. When the Model 30 detects carrier, it allows mobile
audio to pass to the telephone. When carrier drops, and the COR HOLD timer
expires, the Model 30 returns to waiting.
The digital voice delay option board may be installed to enhance the simplex
VOX mode. Since the Model 30 uses the voice detector to know when to key the
transmitter, the first syllable can be lost while the transmitter comes up. CTCSS
decoders can also contribute to the lost syllables. Adding the digital voice delay
board delays the phone audio so that the transmitter will have plenty of time to
get “on line” before the phone audio is passed to the mobile.
Simplex VOX with Prekey
This mode is identical to the above mode, with one exception. When carrier
drops, it is assumed that the telephone will want to start talking, so the Model 30
“prekeys” the transmitter. This reduces the chance of lost syllables while the
transmitter is coming up to full power. If the phone party does not begin speaking

Section 3. Operation
3-7
before the VOX HOLD TIME expires (typically one second), the transmitter
unkeys. The Model 30 then begins watching for either VOX or mobile activity.
Simplex Sampling
When the Model 30 is connected to a radio that switches very fast between
transmit and receive (and is not working through a repeater) the Sampling mode
may be used. There are two parameters that affect sampling modes, they are the
SAMPLE RATE and the SAMPLE WIDTH times. This mode begins with the
transmitter keyed up and audio passing from the telco to the mobile. When the
SAMPLE RATE timer expires, the transmitter is unkeyed and the SAMPLE
WIDTH timer is started. When the SAMPLE WIDTH timer expires, the Model
30 looks for carrier detection. If carrier is not present, the transmitter is re-keyed
and the cycle starts again. If carrier is present, telco to mobile audio is shut down
and mobile to telco audio is opened. Audio is passed from the mobile to the telco
until COR drops and the COR HOLD timer expires; the cycle starts again.
Sampling with VOX to Extend Sample Interval
This mode is identical to SIMPLEX SAMPLING, but the Model 30 looks for
VOX indication also. When VOX is up, the SAMPLE RATE is extended to 4
times the normal sampling time. When the Model 30 detects VOX, the telephone
is speaking, and therefore sampling only needs to happen 1/4 as often.
Intelligent Simplex Mode
When the Model 30 is not working through a repeater (not connected to a control
station), the Intelligent Simplex mode will provide the best possible operation.
This mode uses VOX, the SAMPLE WIDTH timer and audio delay to provide
premium simplex operation. As long as VOX is detected, the transmitter is keyed
and audio is passed from the telco to the mobile. When VOX drops for the
SAMPLE WIDTH time (or more), the Model 30 allows the rest of the audio (still
trapped in the delay) to go out the transmitter. Once the audio is out the
transmitter and silence (the gap) is being transmitted, the transmitter is unkeyed.
Just before the end of the gap reaches the transmitter, carrier is checked. If carrier
is present, the mobile takes over the call. If carrier is not present, the transmitter
is again keyed, and the remaining audio in the delay is allowed out the
transmitter. Using the delay and timing the gap, the Model 30 is capable of
sampling between words without the loss of telephone audio. THIS MODE IS
ONLY AVAILABLE WHEN THE OPTIONAL DIGITAL VOICE DELAY
HAS BEEN INSTALLED.
Simplex Phone Key Control
VOX operation may now be bypassed and transmit & receive can be controlled
by the phone caller using the “*” and “#” keys on a DTMF phone set. Pressing
the “*” momentarily will key the transmitter and the caller may talk. Pressing the
“#” momentarily will unkey it. This allows trained callers to have very positive
control in simplex dispatch operations.

Section 3. Operation
3-8
Simplex Timers
VOX Hold Time
Sets the VOX hold time, or the time that the VOX detection must be gone before
the telco side of the conversation is assumed over. This time should be set to the
minimum required as it slows down the conversation, but a time too short will
cause the conversation to flip to the mobile side prematurely. This timer only
affects the VOX simplex modes.
COR Hold Time
A hold time may be added to the receive carrier detector in simplex mode to
reduce the effects of “picket fencing.” When mobiles operate in fringe areas, or
through multi-path zones, the carrier may momentarily drop. When it does, the
patch will assume that the mobile unkeyed, and could key the transmitter to
allow the phone party to begin speaking. The COR hold time will allow the
receive audio to be muted to the phone party, but won’t assume the mobile has
unkeyed until the COR hold time expires.
Sample Rate
Sets the rate that the Model 30 will sample for carrier. This is NOT the amount of
time that it looks for carrier, but how often it looks. The sample rate timer is used
for simplex sampling, and simplex sampling w/VOX extend. Note that simplex
Intelligent mode does not use this timer.
Auto Sample Setup
This command allows the simplex sample window duration to be set
automatically for any radio. Once the command is executed, the Model 30 will
key the radio for 2 seconds allowing time to generate a DTMF digit into the
receiver using a DTMF equipped radio. The Model 30 will unkey the transmitter
and time how long it takes to decode the DTMF. This is saved as the sample
width time. Commands are available to increment and decrement the sample
window in 10-millisecond increments for fine tuning.
OPTIONS
A Digital Voice Option is available for premium simplex operation.